Had to do factory reset, now unable to download apps from google playstore like youtube etc, any help?

I suggest that you troubleshoot first, instead of a hard reset. Factory reset is within settings.
If any google app won't download nor install, it's probably because your google services are not updated or is corrupted. Try the next steps before factory reset.
1. Go to settings, scroll down to app.
2. From here search for PlayStore and tap it.
3. Tap Clear Cache and Clear data.
4. Go Back.
5. Search now for Google services, this one is not under the download tab, which you can notice at the top of the screen, instead got to All and scroll down until you find it.
6. Tap Clear Cache and Clear data if available.
7. Reboot phone or tablet.
Most of the time this procedure do work, some people also opt to remove the google account and sign in after the reboot.
After the boot, open the PlayStore, accept the agreement and try to download anything from the PlayStore that is compatible with your tablet. Also, just to be sure, go to settings, security, look for Unknown Sources and enable it. This feature allow you to install any apk file that is not from the PlayStore.